Fluorescence imaging system for an operating room

Abstract

Fluorescence imaging system for an operating theatre, comprising a device illuminating the operating theatre and emitting a white light, and a fluorescence imaging device. Said fluorescence imaging device comprises a light source emitting radiation for excitation of a fluorescent marker in a range of emission wavelengths of between 600 and 900 nm. The light emitted by the illuminating device is filtered by a low-pass filter, of which the cut-off wavelength is below the emission range of the fluorescent marker, but is nonetheless able to show an increase or fluctuations in the attenuation for wavelengths above the emission range of the fluorescent marker, the product of the attenuation of the filter of the detector and of the attenuation of the low-pass filter of the illuminating device leading to an attenuation by a factor of at least 10 6 .

The invention claimed is: 
     
       1. A fluorescence imaging system for an operating room, said system comprising:
 an operating room illuminating device capable of emitting white light and 
 a fluorescence imaging device, 
 said fluorescence imaging device comprising:
 a light source capable of emitting excitation radiation in a range of wavelengths of between 600 and 900 nanometers to excite a fluorescent marker; 
 a detector adapted to detect the fluorescent radiation emitted by the marker under the effect of the excitation by the light source; and 
 a filter of the detector comprising a first detector filter and a second detector filter, the second detector filter being a band-pass filter or high-pass filter and being adapted to block the excitation radiation and to transmit to the detector those photons having a wavelength included in the range of wavelengths of fluorescent radiation emitted by the marker, the first detector filter being a first low-pass filter having a first upper cut-off wavelength, 
 
 the system further comprising: 
 a second low-pass filter placed in front of the illumination device and having a second upper cut-off wavelength that is below the emission range of the fluorescent marker, said second low-pass filter nonetheless being able to exhibit attenuation peaking or fluctuations at wavelengths above the emission range of the fluorescent marker, 
 wherein in a range of wavelengths extending from the upper cut-off wavelength and through the wavelengths which the attenuation peaking or fluctuations of the second low-pass filter are observed, the product of attenuation by the filter of the detector and the second low-pass filter leads to an attenuation by a factor of at least 10 6 . 
 
     
     
       2. The system of  claim 1 , wherein the wavelength of excitation radiation is between 630 and 810 nanometers. 
     
     
       3. The system of  claim 1 , wherein the bandwidth in which the filter of the detector transmits fluorescent radiation is between 50 and 70 nanometers. 
     
     
       4. The system of  claim 1 , wherein the range of wavelengths, in which the product of attenuation by the detector filter and of attenuation by the second low-pass filter leads to the attenuation by the factor of at least 10 6 , extends at least as far as the limit detection wavelength of the detector. 
     
     
       5. The system of  claim 1 , wherein the range of wavelengths, in which the product of attenuation by the filter of the detector and of attenuation by the second low-pass filter leads to the attenuation by the factor of at least 106, extends at least as far as 1000 nanometers. 
     
     
       6. The system of  claim 1 , wherein in the range of wavelengths transmitted by the detector filter, the second low-pass filter exhibits attenuation by a factor of at least 106. 
     
     
       7. The system of  claim 1 , wherein the illuminating device comprises a dome-shaped light-head which can be positioned via a hinged arm. 
     
     
       8. The system of  claim 1 , wherein the illuminating device comprises a headlamp. 
     
     
       9. The system of  claim 1 , wherein the illuminating device is adapted to provide continuous lighting. 
     
     
       10. The system of  claim 1 , wherein the illuminating device is adapted to provide pulsed lighting. 
     
     
       11. The system of  claim 1 , wherein the illuminating device comprises light-emitting diodes. 
     
     
       12. The system of  claim 1 , wherein the power of the illuminating device is 40 k-Lux or higher. 
     
     
       13. The system of  claim 1 , wherein the detector is a CCD or CMOS camera. 
     
     
       14. The system of  claim 1 , wherein the excitation wavelength is 780 nanometers and wherein the filter of the detector transmits radiation in a band between 820 and 850 nanometers. 
     
     
       15. The system of  claim 1 , wherein the excitation wavelength is 750 nanometers and wherein the filter of the detector transmits radiation in a band between 780 and 870 nanometers.